Yellow Lab respiratory issues now serious

Hello, my name is Jason, I posted a concern two months ago concerning my dog Andy. At the time his breathing had been raspy. The Vet I had taken Andy to since he was a puppy suggested a full array of bloodwork. I had a second opinion that suggested the same. The tests came back with no results. I then had an X ray done which showed a slightly enlarged heart that may be restricting his breathing, although a specialist would need to perform an ultrasound for a three dimensional view. At this point I am more confused than informed. Yesterday I woke up to Andy whimpering fron my bathroom, completely paralyzed. I took him to a third Vet that gave me a referral to a Neurologist and a suggestion of euthanization. Before I left they injected about a quart of IV fluid into him. I have been camped out next to him since. Through searching the internet, in desperation I came across laryngeal paralysis and an operation that could address it. I have an appointment tomorrow with another Vet that is familiar with the condition. I've done about three hours of reading and this comes close. He barks due to restricted breathing, his breathing has been raspy when any activity takes place. This condition is most common in older male Labs. I am to the point of pleading if anyone has any insight. I am almost sorry for the picture, I am very worried. Thank you.

A dog at rest takes about 10 to 30 breaths per minute. Breathing at a faster rate suggests fever, pain, anxiety, or a problem with the lungs or chest. Rapid breathing should be distinguished from panting. Panting is the primary way a dog lowers her body temperature; water evaporates from the mouth, tongue, and lungs, and warm air in the body is exchanged for cooler air in the atmosphere. Rapid breathing, when accompanied by labored or difficult breathing, is a sign of distress. Dogs with congestive heart failure and/or lung disease often have rapid, labored breathing at rest or with only mild exertion. Other causes of rapid, labored breathing are shock, heat stroke, dehydration, and ketoacidosis associated with diabetes, kidney failure, and some kinds of poisoning.

Maybe the best advice would be to look for some expert Veterinary Pharmacist as they would advise good on this account.